1. Field of the Invention
Embodiments of the invention relate to memory devices, and more particularly, to post-packaging repair of memory devices.
2. Description of the Related Art
Memory cells of memory devices such as dynamic random access memories (DRAMs) can experience failures. Failures can occur after the memory device (e.g., a memory chip) has been packaged. After a memory device has been packaged, the memory device can be tested to identify defective memory cells. Addresses mapped (e.g., assigned) to defective memory cells can be remapped (e.g., reassigned) to redundant memory cells so that the memory device can still be effective.
A group of programmable elements can be programmed to store the remapping. One example of a group of programmable elements includes a row of antifuses. An antifuse has a high resistance in its initial state. An antifuse can permanently create an electrically conductive path when a relatively high voltage is applied across the antifuse. An antifuse can have a structure similar to that of a capacitor, i.e., two conductive electrical terminals are separated by a dielectric layer. To create an electrically conductive path, a relatively high voltage is applied across the terminals, breaking down the interposed dielectric layer and forming a conductive link between the antifuse terminals. Creating a conductive path through an antifuse is referred to as “blowing an antifuse.”